Caption: MODEL RELEASED. Elbow replacement surgery. Image 3 of 11. Surgeons drilling into a patient's humerus (upper arm bone) during elbow replacement surgery. A metal jig is being used to align the drill and keep it steady during the surgery. Joints may need to be replaced due to injury or disease, such as arthritis as in this case. For a sequence showing the operation see M551/407-M551/417.